1. Field of the Invention
The subject invention relates to material transport equipment and, more specifically, to apparatus for advancing cards or sheets of paper or other material.
2. Description of the Prior Art
The need for apparatus for advancing sheets of material is well known and recognized and touches upon the fields of manufacture and processing as well as on areas of the data handling and processing art.
Most commonly available equipment for transporting sheets of material employ rollers or belts to achieve the the requisite translation of the sheets. Such equipment requires precise alignment of the various parts of the driving or transporting system to insure that the paper proceeds on the desired path without skew and in the proper laterally referenced position.
The basic problem of such transporting equipment is the inability to provide "slip" in an orthogonal direction (in the plane of the sheet) to the desired direction of travel.
A further problem is the difficulty of existing equipment to hold the sheet within the desired limits describing a plane, without adding friction sufficient to cause buckling or tearing, and without encumbering operations, such as sensing or marking, associated with the transport of the sheet.
How little existing proposals in other areas are adaptable to a solution of the above mentioned problems may be seen from the following issued patents:
U.S. Pat. Nos. 2,811,920, by J. T. Richardson, issued Nov. 5, 1957, 3,389,907, by L. H. Turner, issued June 25, 1968, 3,411,772, by H. Rovin, issued Nov. 19, 1968, 3,618,935, by George F. Howatt, issued Nov. 9, 1971, and 3,715,115, by W. Grobman, issued Feb. 6, 1973.